Due to the wide availability, popularity and convenience of wireless local area network (WLAN) communications, such as those conforming to Institute for Electrical and Electronic Engineers (IEEE) 802.11 protocols, it may be desirable for one device to participate in multiple network contexts. Examples of conventional network roles include a station (STA) and an access point (AP) in an infrastructure network or a peer to peer (P2P) client and a P2P group owner (GO) in a WiFi Direct™ network. As such, a single device may participate in multiple networks, acting in an appropriate role for each network context. Such devices, known as concurrent devices, may satisfy the separate roles by spending sufficient time operating in each context to maintain the respective communication links. Often, coordination of the time spent in each network context involves participating in each network at designated times in order to send or receive scheduled network communications, such as a beacon that is sent at specified intervals and used to coordinate and synchronize devices participating in that network. For example, a multi-channel concurrent device may operate as a STA in a first network on one wireless channel and an AP in a second network on another wireless channel. As a practical matter, each network may operate on a separate wireless channel so that a minimum level of participation involves the device switching channels at intervals in order to receive the beacon being sent on the first network and to broadcast the beacon for the second network.
Further, depending upon desired performance characteristics and available resources, WLAN devices may form a variety of different links. One such link is typified by the formation of a basic service set (BSS) in which devices acting as STAs may associate with an AP, such that communications to and from the STAs are routed through the AP. However, it may be desirable for two STAs to form a direct link with each other, avoiding the AP. For example, Tunneled Direct Link Setup (TDLS) is a protocol that allows two STAs to establish a direct link with each other. Under this protocol, frames may be passed directly between the participating STAs once initial negotiations to establish capabilities and set parameters are conducted though the AP.
Although notable benefits are associated with the use of a direct link, conventional TDLS power management techniques may interfere with concurrent operation in another network context. In an exemplary usage scenario, data for a first STA having a TDLS link with a second STA may be buffered at the second STA when the first STA is unavailable on the direct link, such as when the first STA is in power save mode or performing a role in different network context on another channel. The second STA may communicate the existence of the buffered data through use of a peer traffic indication (PTI) frame that is relayed through the AP. Upon receipt of the PTI frame, the first STA sends a peer traffic response (PTR) trigger frame directly to the second STA. This establishes an interval during which the second STA delivers all the data that has been buffered for the first STA. This interval may exist for the amount of time required to successfully transmit the buffered data, as the second STA will continue to send buffered data until all has been delivered.
However, if the first STA is a multi-channel concurrent device as discussed above, it may periodically operate on other wireless channels, such as to perform the minimum obligations in each network context in order to maintain the links. Accordingly, the multi-channel concurrent device may operate for a limited period of time on one channel before being scheduled to switch to another channel associated with a separate network context in order to satisfy its role in that context. If the amount of data buffered at the second STA is too large, the time required to deliver all the data may exceed the amount of time allotted to the first STA for operating on the direct link channel in the current period. As a result, the first STA must either switch channels and miss receiving the buffered data that remains or disrupt operation in the other network context by not participating as scheduled.
Accordingly, the techniques of this disclosure provide systems and methods for allowing a multi-channel concurrent wireless communications device to communicate timing information regarding scheduled availability on the direct link channel to a peer. In turn, the peer may then coordinate delivery of the buffered traffic based, at least in part, on the timing information to reduce interference with operation of the device in another network context.